Initial Definition and 1000 Threads

  1. A

    Effect of Pressure on the Initial Rate

    Hi, Let's suppose an elementary reaction of the low-pressure mixture has the initial reaction rate of x (2A + B --> A2B). What would be the initial reaction rate of the high-pressure mixture? (Imagine a mass M is placed upon the beaker filled with the mixture, and a mass 3M is placed upon...
  2. A

    Trying to determine initial thrust on an object from angular velocity?

    Hi all, I built an electric paper airplane launcher and I'm trying to figure out how much force or thrust is being applied to my paper airplane when it's launched. The setup looks like this: The discs are 124mm in diameter, are spinning at approximately 5800 RPM each, and are about...
  3. skate_nerd

    Coulombs law, initial speed to collide with other nucleus

    Homework Statement A helium nucleus has radius rHe = 1.9 fm, mass m = 6.6 × 10-27 kg, and charge +2e. A gold nucleus has charge +87e and radius rAu = 7.0 fm. What initial speed must a helium nucleus have if it is to come into contact with a fixed gold nucleus in a head on collision...
  4. N

    Differential Equations and Initial Values

    Homework Statement If y is the solution of the initial value problem y'(t) + y(t)/t = 1/t4 y(2)=1 What is y(3) Homework Equations The Attempt at a Solution I u(t) = e∫1/t dt = eln t = t ∫[yt]' dt = t-4 dt yt = -1/3t3 + C Plugging in my initial value I solve for...
  5. S

    Find Direction and Angle to arrive directly across initial location?

    Homework Statement A boat can go 12 km /h in a river that has current of 5 km /h. At what angle relative to the shore does the boat have to leave to arrive directly across from initial location? Homework Equations SOH CAH TOA The Attempt at a Solution I just want some...
  6. H

    Initial displacement in Simple Harmonic Motion

    Homework Statement A meterstick is clamped to a tabletop. The end of the meter stick is deflected downwards a small distance x and is released such the end of the meterstick moves up and down in simple harmonic motion. The meterstick is measured to oscillate up and down 10 times in 5.0...
  7. I

    Find Initial Velocity from Angle and Horizontal Distance

    Homework Statement "An athlete executing a long jump leaves the ground at a 30.0° angle and travels a horizontal distance 8.00m. What was the take-off speed?" Let ##x=## horizontal distance ##v=## velocity ##a=## acceleration Known: ##x=8 m## ##x_0=0 m## ##a_y=-9.8 m/s^2##...
  8. MarkFL

    MHB Kavina's question at Yahoo Answers regarding an initial value problem

    Here is the question: Here is a link to the question: Calculus question on differential equations? - Yahoo! Answers I have posted a link there to this topic so the OP may find my response.
  9. I

    Resultant vector given initial velocity and acceleration

    Homework Statement http://postimage.org/image/466vu4yvp/ http://postimage.org/image/opdrmlv5n/ There can be more than one right answer Homework Equations α=Δv/ΔX v = v0 + αt The Attempt at a Solution Im having difficulty understanding the upward acceleration vector. Because I set the +y...
  10. D

    Magnitude of Initial velocity of Spacecraft

    On a spacecraft two engines fire for a time of 572 s. One gives the craft an acceleration in the x direction of ax = 5.15 m/s2, while the other produces an acceleration in the y direction of ay = 7.41 m/s2. At the end of the firing period, the craft has velocity components of vx = 3782 m/s and...
  11. 2

    (Easy) Finding initial velocity from uniform acceleration

    Hi, I don't know what I'm doing wrong but these significant figures seem to be screwing me up. Problem: A bike rider accelerates constantly to a velocity of 7.5 m/s during 4.5 s. The bike's displacement is +19 m. What was the initial velocity of the bike? The textbook says the answer is 0.94...
  12. S

    Determine initial and final temperatures, adiabatic expansion?

    Homework Statement A 3.25 mol sample of an ideal diatomic gas expands adiabatically from a volume of 0.1050 m^3 to 0.762 m^3. Initially the pressure was 1.00 atm Determine the initial and final temperatures Homework Equations PVγ= nRT The Attempt at a Solution To get the initial...
  13. A

    PDE: Initial Conditions Contradicting Boundary Conditions

    Suppose we have the following IBVP: PDE: u_{t}=α^{2}u_{xx} 0<x<1 0<t<∞ BCs: u(0,t)=0, u_{x}(1,t)=1 0<t<∞ IC: u(x,0)=sin(πx) 0≤x≤1 It appears as though the BCs and the IC do not match. The derivative of temperature with respect to x at position x=1 is a constant 1...
  14. E

    2nd order initial value problem in matlab

    Homework Statement 1.)I want to write a function in MATLAB that contains the 2nd order function: 20*d^{2}x;(dt^{2})+5*dx/dt + 20*x=0 (dampened spring) -The function should have 2 inputs (time,[initial values]) initial values should be a vector of 2 values -The function should...
  15. C

    Find a solution to the initial value problem

    Homework Statement Find a solution to the initial value problem that is continuous on the interval where Homework Equations I know the equations, but don't want to type them out.The Attempt at a Solution I got the first part of this question. The part where g(t) = sin(t) I can not figure...
  16. S

    F = MA Exam 2010 #'s 15,16 (Two mass system with initial velocity)

    Homework Statement See: http://www.aapt.org/physicsteam/2010/upload/2010_FmaSolutions.pdf #15, 16 Homework Equations U_o + K_o = U + K v_CoM = vM1 + vM2 / (M1 + M2) The Attempt at a Solution I thought that for 15 it was simply: 1/2mv^2 = mgh h = v^2/2g But this is wrong, so...
  17. M

    A ball is dropped twice off the same initial height. trial one bounces

    a ball is dropped twice off the same initial height. trial one bounces back with a velocity of 3m/s and trial 2 bounces back with a velocity of 2m/s. the time the ball is in contact with the ground for trial 1 is 0.01s. are the impulses on the ball the same for both trials or is it less in trial 2?
  18. C

    Find the unique solution to the initial value problem

    Homework Statement The unique solution to the initial value problem is http://webwork.usi.edu/webwork2_files/tmp/equations/ed/12ad7dca5df62ed3b18f5fbf8c6e871.png Determine the constant and the function Homework Equations Not sure for the second part. The Attempt at a...
  19. R

    What Was the Initial Velocity of the Bullet in the Momentum Problem?

    Homework Statement A bullet of mass 12.0 grams is traveling with a speed V0 and strikes a block of mass M = 1.00 kg that rests on a horizontal surface (mu = 0.40). After the bullet imbeds in the block, it slides 2.60 meters before coming to rest. The initial velocity of the bullet must have...
  20. P

    N-Body Problem - Initial Values

    Hello everyone, I'm new here so let me introduce myself first: I'm a games engineering student and my main field is programming Right now I'm struggeling with the N-Body Problem, well I think actually solved parts of it: I've implemented the basic equations with a leapfrog algorithm...
  21. U

    Solving a First Order Differential Equation with Initial Conditions.

    Homework Statement Solve the initial value problem: t(dy/dt)+8y=t^3 where t>0 and y(1)=0 Homework Equations None? The Attempt at a Solution It's a linear equation, so rearranged to dy/dt+8y/t=t^2. Took the integrating factor e^(∫8/tdt)=t^8 and multiplied through...
  22. S

    Oscillations: Pendulum with initial velocity

    Homework Statement A child on a 4m long swing is pulled back 1m from the vertical and released with a push imparting a speed of 2m/s. Find an expression for the angle θ, as a function of time, identifying the frequency ω, amplitude θi, and phase constant δ. Homework Equations θ =...
  23. P

    How to calculate initial velocity and launch angle? (Projectiles)

    Homework Statement A bean bag launcher is used to shoot a bean bag at a corn hole board. The bag is released at a height of .61m above the ground. The front of the board is 5.18m from the location where the launcher releases the bean bag. The back of the board stands .31 m off the ground; the...
  24. B

    Initial Segment X: Does It Include Elements >x?

    Let X be an initial segment of a set A. By definition, if x is in X, a is in A and x>a then a is in X too. Can we say that some elements of A that are greater than x are also in X? Or X only consists of elements smaller than x?
  25. A

    Initial yield stress Vs. tensile strength

    Are those the same? if not, how do I calculate the initial yield stress from the tensile strength? all the materials properties I see on the web only specify tensile strength, and I need the initial yield stress as an input on non-linear FEA analysis. Is it possible to extract the initial yield...
  26. A

    Find P_300 Given P_299: Initial State Vector Homework

    Homework Statement Suppose that the initial vector P0 is not given and instead we are given that at time t=299 the state vector is P_299=[.1 .1 .8]. Than find P_300, the state vector at time t=300 Homework Equations I also know from the problem it is referencing that the transition...
  27. G

    Does logarithmic decrement depend on initial amplitude?

    Lets say we have a weight attached to a spring. When releasing it under water (whole motion occours under water) at different initial amplitudes, will logarithmic decrement be the same? And will the period change? I think it should be the same for different initial amplitudes. But...
  28. B

    Ratio of Damped to Initial Oscillation Amplitudes - 20 Cycles

    In the figure below, a damped simple harmonic oscillator has mass m = 300 g, k = 95 N/m, and b = 70 g/s. Assume all other components have negligible mass. What is the ratio of the amplitude of the damped oscillations to the initial amplitude at the end of 20 cycles (Adamped / Ainitial)? I...
  29. M

    Calculating the Ka from pH and initial concentration

    Homework Statement A 0.0200 mol/L acid solution has a pH of 2.347. Calculate the percent ionization of this acid. Calculate the Ka of this acid The Attempt at a Solution I first calculated the hydronium ion concentration: 10^-pH = 10^-2.347 = 4.5*10^-3 I then used this concentration...
  30. M

    How to Solve for Initial Value in an Integration Problem?

    Homework Statement Solve for initial Value The attempt at a solution http://store2.up-00.com/Sep12/RjY55784.jpg
  31. H

    Finding the initial velocity of a vector

    Homework Statement An object that is thrown covers a distance of 8.59 m. If the angle at which it is thrown is 23 degrees, what is its initial velocity? Homework Equations 5 kinematic equations: a = (v2-v1)/t d=0.5(v1+v2)t d=v1t+0.5at^2 d=v2t-0.5at^2 v2^2=v1^2+2ad Equation for...
  32. A

    Initial Velocity of Projectile Motion, given displacement and initial angle?

    Homework Statement A grasshopper jumps 1.00 meters from rest, with an initial velocity at a 45.0° angle with respect to the horizontal. Find (a) the initial speed of the grasshopper and (b) the maximum height reached.Homework Equations vx = v0xt = v0cos θ0 vy = v0 sin θ0 - gtThe Attempt at a...
  33. O

    D'Alembert solution of wave equation with initial velocity given

    Hi there, This is a problem concerning hyperbolic type partial differential equations. Currently I am studying the book of S. J. Farlow "Partial differential equations for scientists and engineers". The attached pages show my problems. Fig. 18.4 from case two (which starts in the lower part...
  34. D

    Second Order Differential Initial Value Problem

    Homework Statement y''+4y'+6y y(0) = 2; y'(0) = 4 Homework Equations \alpha ± β = e^{x\alpha}(cosβx + sinβx) The Attempt at a Solution Auxilary equation is r^2+4r+6, which solves for -2 ± i I get the general solution: e^{-2x}(c1cosx + c2sinx) y' = -2e^{-2x}(c1cosx +...
  35. M

    Find the Initial and Final states of an excited Hydrogen Atom

    Homework Statement A hydrogen atom in an excited state absorbs a photon of wavelength 434 nm. What were the initial and final states of the hydrogen atom? Homework Equations 1/λ=1/91.127 * (1/nf2-1/ni2) The Attempt at a Solution Tried to use the equation, but keeping the initial...
  36. A

    Chemistry How to Find Initial Moles of Reactants for Given Reaction | Moles Homework

    Homework Statement We are given a reaction: H2O2 + 2I- + 2H+ → 2H2O + I2 and are asked to find the initial number of moles of each reactant. V=10mL and C=0.2 mol/L for potassium iodide in the solution. V=5mL and C=0.5 mol/L for sulfuric acid in the solution. V=5mL and C=0.02 mol/L for...
  37. T

    Maximum Initial Speed of an Overdamped Oscillator

    Homework Statement An overdamped oscillator with natural frequency w and damping coefficient y starts out at a position xo>0. What is the maximum initial speed (directed toward the origin) it can have and not cross the origin? Homework Equations Overdamped Case Equation...
  38. D

    How to calculate initial concentration

    Homework Statement A known mass of methylamine, CH3NH2, was dissolved in water at 25 celsius 50.0 cm^3 of this solution was taken and titrated with 1.00x10^-1 mol dm^-3 hydrochloric acid solution, HCL(aq). The change in pH as an increasing volume of hydrochloric acid was added is shown in the...
  39. Z

    Determining initial velocity of an electron

    Homework Statement Consider an electron that has its position measured to within a nuclear radius in a laboratory. What is the uncertainty in its position uncertainty one day later? Homework Equations The Attempt at a Solution What equation should I use to determine the...
  40. T

    Final Velocity given only Initial Velocity and Angle

    Homework Statement This is a homework that has me completely stumped. If anyone help me out here, I would greatly appreicate it. A billard ball is east at 2.0 m/s. A second, idential ball is shot west at 1.0 m/s. The balls have a glancing collision (not head-on), deflecting the second ball...
  41. G

    How Do You Calculate Initial Velocity Components Given Angle and Distance?

    Homework Statement I need help finding the x and y components of initial velocity being given the angle the trajectory was fired at and the distance the projectile traveled. For this example I'm using an angle of 15° and the projectile travels 0.534m. I'm not sure if I'm going in the right...
  42. D

    MHB Solving the Heat Equation with Initial Conditions

    I have already solved the main portions. I have $$ T(x,t) = \sum_{n = 1}^{\infty}A_n\cos\lambda_n x\exp(-\lambda_n^2t) $$ The eigenvalues are determined by $$ \tan\lambda_n = \frac{1}{\lambda_n} $$ The initial condition is $T(x,0) =1$. For the particular case of $f(x) = 1$, numerically...
  43. C

    Can't finish a Laplace Initial Value Problem.

    I've had to take diff eqtns now and I'm trying to get my head around Laplace again.. it's been a while. I can't seem to transition to the simplest step of partial fractions, my denominators are tough to figure out. If someone could point me to the next step that'd be great! Thanks a lot guys...
  44. 1

    Finding initial velocity for projectile motion at 0 degrees

    I am doing a projectile motion problem with my own results, and the unknown's of initial velocity and time. It is at 0 degrees, which I thought would mean I could find the vertical down of the projectile (where at an angle you find the vertical up and down because it goes up first). I have tried...
  45. F

    Solution to a PDE (heat equation) with one initial condition

    Homework Statement By trial and error, find a solution of the diffusion equation du/dt = d^2u / dx^2 with the initial condition u(x, 0) = x^2. Homework Equations The Attempt at a Solution Given the initial condition, I tried finding a solution at the steady state (du/dt=0)...
  46. D

    What is the Initial Velocity of a Cannon Ball Fired at 45 Degrees?

    Homework Statement A cannon ball weighing 128 pounds is fired from a cannon at 45 degrees above the horizontal. The cannon ball lands in a pool that has a radius of 14 feet and located 7.5 feet above the ground. The closest edge of the net is 98 feet from the cannon. It takes 4 seconds for the...
  47. U

    Calculate the initial velocities of buggies

    Homework Statement Two identical buggies 1 and 2 with one man in each move without friction due to inertia along the parallel rails toward each other. When the buggies get opposite each other, the men exchange their places by jumping in the direction perpendicular to the motion direction. As a...
  48. R

    Solving an Initial Velocity Problem for a Basketball Player

    1. Homework Statement A basketball player is standing 9.5 m from the basket, which is at a height of 3.1m. she throws the ball from a initial height of 2m at an angle of 35 degrees above the horizontal. The ball goes through the basket. Determine intial velocity. 2. Homework...
  49. R

    Solving Basketball Parabola Puzzle: Initial Velocity at 35°

    Homework Statement A basketball player is standing 9.5 m from the basket, which is at a height of 3.1m. she throws the ball from a initial height of 2m at an angle of 35 degrees above the horizontal. The ball goes through the basket. Determine intial velocity. PS Assume the max height of the...
  50. C

    Initial Compressed Spring Force

    Homework Statement A spring has a relaxed length of 0.17 m, and its stiffness is 15 N/m. The spring sits vertically on a table. You place a block of mass 0.058 kg on the spring and push down on the block until the spring is only 0.11 m long. You hold the block motionless on the compressed...
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